Publicis Groupe's Zenith Optimedia today issued a revised global ad forecast for 2010, projecting a 2.2 percent rise in spending to $456 billion. The upgrade represents an improvement of more than a full percentage point vs. ZO's December forecast of a 0.9 percent gain in ad spending for the year.

The revised outlook is generally in line with an upgrade issued late last month by Aegis Group's Carat, which predicted that worldwide ad spending would climb 3 percent this year.

But the two shops diverged over the direction of U.S. spending in their forecast revisions. Carat predicted a slight domestic gain (0.2 percent) this year. ZO, however, believes domestic spending will drop 2 percent, while finally moving into positive territory in 2011.

Neither shop broke out U.S. figures. But in its revised offering, ZO gauged North American spending (the bulk of which is U.S.) for full-year 2010 at $154.5 billion, down 1.5 percent. For 2011, ZO expects spending in the region to finally reverse course and climb almost 2 percent to $157.3 billion.

In its revised forecast, ZO said Western Europe would inch ahead 0.4 percent this year to about $108 billion. The agency said that Asia-Pacific region would improve about 6 percent, also to $108 billion.

ZO said the rise of the Internet as a vibrant ad medium continued uninterrupted during the recession.

"In fact, the downturn probably accelerated the shift of budgets from traditional media by focusing advertisers' minds on the importance of measurable return on investment," the agency said.

The Internet boosted its share of global ad spending to 12.6 percent in 2009, up from 10.5 percent in 2008, ZO said, overtaking magazines to become the third-largest spending segment, behind only newspapers and television. Magazines fell to a 10.3 percent share last year from an 11.6 percent share in '08.

TV, newspapers and the Internet will remain the three largest ad spending segments -- in that order -- through 2012, per ZO.

But the gap between Internet and newspaper spending will continue to narrow.

By 2012, Internet ad outlays will climb to a 17.1 percent share of the pie, while newspapers' share will fall to 19.4 percent from 21.7 percent this year. TV's share will climb slightly, from 40.3 percent to 40.6 percent during the same period, per ZO's forecast.